mediaton using regression analysis

1. Mediation
Michael Sony
emailofsony@gmail.com

2. Hallmark of Well Specified Conceptual
Model*
1. Antecedents
2. Mediators
3. Moderators
4. Consequences
Varadarajan, P. R. (1996). From the editor: Reflections on research and publishing.
Journal of Marketing, 60(4), 3-6.
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3. An Example
Students
Intelligence
Classroom
Performance
Moderator
Study
Hardworking
Effectiveness
Lazy /
Antecedents Mediator Consequences
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4. Mediation
• A variable mediates the relationship between
two other variables.
Independent
Variable
Dependant
variable
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5. Mediation
Independent
Variable
Dependant
variable
Mediating
Variable
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6. Basic Types of Mediation
• No Mediation
Independent
Variable
dependent
Variable
Mediating
Variable
Direct Effect
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7. No Mediation
IV DV
M
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8. Basic Types of Mediation
• Full Mediation
Independent
Variable
dependent
Variable
Mediating
Variable
Indirect Effects
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9. Full Mediation
IV M DV
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10. Basic Types of Mediation
• Partial Mediation
Independent
Variable
dependent
Variable
Mediating
Variable
Direct + Indirect Effects
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11. Partial Mediation
IV DV
M
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12. Testing for mediation using
Hierarchical Multiple Regression
Models
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13. Baron and Kenny Approach to
Mediation Testing
Step 1: Independent Variable is related to
Dependant Variable ( Significant relation) else no
mediation
Independent
Variable
Dependant
Variable
c
Baron, R. M., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological
Workshop on Research Methodology
research: Conceptual, strategic, and statistical considerations. Journal of personality and social psychology,
GUDMS
51(6), 1173.

14. Baron and Kenny Approach to
Mediation Testing
Independent
Variable
Mediating
Variable
Dependant
Variable
a b
C’
Step 2: Independent Variable is related to Mediating Variable ( Significant
relation) else no mediation
Baron, R. M., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological
Workshop on Research Methodology
research: Conceptual, strategic, and statistical considerations. Journal of personality and social psychology,
GUDMS
51(6), 1173.

15. Baron and Kenny Approach to
Mediation Testing
Independent
Variable
Mediating
Variable
Dependant
Variable
a b
C’
Step 3:Mediating Variable is related to Dependant Variable ( Significant
Correlation) else no mediation controlling for IV
Baron, R. M., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological
Workshop on Research Methodology
research: Conceptual, strategic, and statistical considerations. Journal of personality and social psychology,
GUDMS
51(6), 1173.

16. Baron and Kenny Approach to
Mediation Testing
Independent
Variable
Mediating
Variable
Dependant
Variable
a b
C’
Step 4: Check again -Independent Variable is related to Dependant
Variable ( Significant Correlation) with the mediator variable
Baron, R. M., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological
Workshop on Research Methodology
research: Conceptual, strategic, and statistical considerations. Journal of personality and social psychology,
GUDMS
51(6), 1173.

17. C’
C’ not
significant
Full Mediation
C’ is
Significant
but strength is
decreased –
Perform
Sobels test
Partial
mediation
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18. Sobels Test
• The Sobel test performed best in a Monte
Carlo study (MacKinnon, Warsi, & Dwyer,
1995), and converge closely with sample sizes
greater than 50.
MacKinnon, D. P., Warsi, G., & Dwyer, J. H. (1995). A simulation study of mediated
effect measures. Multivariate behavioral research, 30(1), 41-62.
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19. Sobels Test
• Step 1: Simple Regression Independent Variable on
Dependant variable note unstandardised Beta (c) ,
Standard error (SEc)and beta Standardised value (βc).
• Step 2: Simple Regression Independent Variable on
Mediator note unstandardised Beta(a), Standard error
(SEa)and Standardised value (βa)
• Step 3: Multiple Regresion Independent, Mediator
variable on Dependant variable note unstandardised
Beta (b), Standard error (SEb)and Standardised value
(βb) coefficient between M and Y
• Step 4: Same but note coefficient Independent Variable
and Dependant VaWroirakshbopl eon R(ecse’ar)ch Methodology
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20. Sobels Test
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21. Example 1
• Proposed model
Environmental
Perception
Job Satisfaction
Staying
Intention
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22. Example 2
• Alternative model
Environmental
Perception
Staying
Intention
Job Satisfaction
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23. Reflection Question
• Which model in previous two examples
explains the data better?
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24. Example 3
• Proposed model
Environmental
Perception
Staying
Intention Job Satisfaction
Attitude
Towards Co-workers
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